Add coverage badge

Cargo.toml

@@ -21,6 +21,7 @@ include = [
 
 [badges]
 travis-ci = { repository = "eldruin/ds323x-rs", branch = "master" }
+coveralls = { repository = "eldruin/ds323x-rs", branch = "master", service = "github" }
 maintenance = { status = "actively-developed" }
 
 [dependencies]

README.md

@@ -3,6 +3,7 @@
 [![crates.io](https://img.shields.io/crates/v/ds323x.svg)](https://crates.io/crates/ds323x)
 [![Docs](https://docs.rs/ds323x/badge.svg)](https://docs.rs/ds323x)
 [![Build Status](https://travis-ci.org/eldruin/ds323x-rs.svg?branch=master)](https://travis-ci.org/eldruin/ds323x-rs)
+[![Coverage Status](https://coveralls.io/repos/eldruin/ds323x-rs/badge.svg?branch=master)](https://coveralls.io/r/eldruin/ds323x-rs?branch=master)
 ![Maintenance Intention](https://img.shields.io/badge/maintenance-actively--developed-brightgreen.svg)
 
 This is a platform agnostic Rust driver for the DS3231, DS3232 and DS3234